Three-element leaky antenna array structure and design method based on dielectric ridge parallel plate waveguide

Abstract

This invention discloses a three-element leaky wave antenna array structure based on a dielectric ridge parallel plate waveguide, comprising: S1, designing a three-element array structure based on the coupling characteristics of the dielectric ridge parallel plate waveguide, wherein the two-port array antenna is fed by probes in parallel; S2, determining the slot design of the three elements according to the pattern product theorem and the relationship between slot size and leakage, thereby designing a scanning beam that meets the requirements of narrow beamwidth and high gain. This invention is a leaky wave antenna array structure with narrow beamwidth and high gain characteristics proposed to meet the requirements of high signal strength and strong anti-interference in long-distance point-to-point communication systems. This antenna can provide better directivity and higher communication quality, while ensuring that the antenna has the advantages of compact structure and small size, thus it can be applied to wireless power transmission systems such as satellite communication systems, radar systems, and the Internet of Things.

Description

Technical Field

[0001] This invention relates to the fields of electronics and communication technology, specifically to a three-element leaky wave antenna array structure and design method based on a dielectric ridge parallel plate waveguide. Background Technology

[0002] With the rapid development of wireless communication and wireless power transfer technologies, the demand for broadband, high-efficiency, and high-gain antennas with beam scanning capabilities is increasing. Therefore, leaky wave antennas (LWAs), as high-gain antennas with inherent beam scanning capabilities, have attracted widespread attention in low-cost and high-capacity communication systems.

[0003] To improve the bandwidth of leaky wave antennas, researchers have conducted extensive work. Common methods include improving traditional waveguide structures, such as replacing traditional substrate integrated waveguides (SIWs) with ridge substrate integrated waveguides (RSIWs) and comb-shaped substrate integrated waveguides (CSIWs). Open transmission line structures have also been widely used in the design of broadband frequency-scanning leaky wave antennas in recent years, such as microstrip lines, biased parallel striplines, coplanar stripes (CPSs), right- / left-handed transmission lines (CRLH-TLs), and spoof surface plasmon polaritons (SSPPs). However, the efficiency of existing broadband leaky wave antennas remains limited. Similarly, improving the efficiency of beam-scanning leaky wave antennas has received considerable attention. Using energy-circulating feed networks or designing novel slots to increase energy leakage are effective main methods to improve antenna efficiency. However, the operating bandwidth of existing high-efficiency leaky wave antennas remains relatively narrow. Therefore, designing highly efficient broadband leaky-wave antennas remains a challenging problem. While wide-beam antennas are suitable for applications requiring continuous and reliable communication, signal strength and anti-interference capabilities are particularly important in long-distance point-to-point communications, such as satellite communications, radar systems, and wireless power transmission applications like the Internet of Things. In these applications, narrow-beam, high-gain antennas can provide superior directivity and higher-quality communication.

[0004] To balance bandwidth and efficiency, researchers mostly employ periodic planar transmission structures to design leaky-wave antennas. The most similar implementation to this invention is proposed in Z. Li et al., “Investigation of Leaky-Wave AntennaWith Stable Wide Beam-Scanning Characteristic,” in IEEE Transactions on Antennas and Propagation, vol. 70, no. 1, pp. 240-249, Jan. 2022, doi:10.1109 / TAP.2021.3111486., which uses a CRLH-TL design for the leaky-wave antenna. This achieves an average efficiency of 80% and a 45% operating bandwidth, but requires the design and fabrication of additional radiating structures and has limitations in terms of integration.

[0005] In summary, a novel leaky wave antenna structure with narrow beamwidth, wide bandwidth, and high efficiency is proposed to address the problems existing in current frequency-scanned leaky wave antennas, which is one of the hot research directions for researchers in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a three-element leaky wave antenna array structure based on a dielectric ridged parallel-plate waveguide (DRPW). The narrow-beam, high-gain array design proposed for the high-directivity signal strength requirements in long-distance point-to-point communication allows the antenna to achieve continuous beam scanning with a wide operating bandwidth and high efficiency, thereby providing continuous and reliable signals.

[0007] The technical solution adopted in this invention is as follows:

[0008] In a first aspect, the present invention provides a design method for a three-element leaky antenna array structure based on a dielectric ridge parallel plate waveguide, the method comprising:

[0009] S1: Design a three-element array structure based on the coupling characteristics of the dielectric ridge parallel plate waveguide. The two-port array antenna of the structure is fed by probes in parallel.

[0010] S2: Based on the pattern product theorem, the slot design of the three units is determined according to the relationship between the slot size and the leakage amount, so as to design a scanning beam that meets the requirements of narrow lobe and high gain.

[0011] Furthermore, S1 specifically includes:

[0012] S11: Select the spacing between two adjacent dielectric ridges based on the coupling characteristics of the dielectric ridge parallel plate waveguide. p d This allows for the design of a three-element waveguide array with a small lateral dimension while ensuring minimal inter-waveguide coupling. In other words, the designed waveguide array exhibits low inter-waveguide coupling while maintaining a compact array structure. The DRPW structure includes an upper metal layer, a dielectric ridge, and a lower metal layer. The coupling effect is determined by the coupling coefficient. C Determining the magnitude of the values, C Based on the propagation constants of odd and even modes of the DRPW coupled field β o and β e Confirmed, the specific formula is as follows:

[0013] ;

[0014] S12: Connect the two ends of the dielectric ridges in the three DRPW units of the waveguide array to form a complete dielectric layer; the waveguide array adopts probe parallel feeding, that is, the probe is placed at the intersection of the three dielectric ridges, and a load is set at the end of the array to absorb the remaining energy transmitted to the end.

[0015] Furthermore, S2 specifically includes:

[0016] S21: Determine the required radiation intensity difference for the three DRPW arrays according to the pattern product theorem to obtain a leaky antenna array with a narrower beam compared to a single leaky antenna; the radiation intensity of the leaky antenna element in the middle is greater than that of the two leaky antennas on both sides, and in order to ensure that the pattern is not distorted, the radiation intensity of the leaky antennas on both sides is kept consistent.

[0017] S22: Design slot arrays of different sizes on the DRPW array according to the required radiation intensity, that is, etch slot arrays on the upper metal plate of the three DRPW units; wherein, the radiation capacity of the slot arrays located on both sides is equal and less than that of the slot array located in the middle.

[0018] On the other hand, the present invention also provides a three-element leaky wave antenna array structure based on a dielectric ridge parallel plate waveguide. The structure includes an upper metal plate, rectangular slot array I, rectangular slot array II, and rectangular slot array III engraved on the upper metal plate for energy leakage radiation, a dielectric layer, a lower metal plate, probe holes for power feeding, and screw holes for fixing the overall structure.

[0019] Furthermore, the upper metal plate and the lower metal plate form an upper and lower parallel metal plate, and the three units share the upper and lower parallel metal plate.

[0020] Furthermore, the rectangular slot array I, rectangular slot array II, and rectangular slot array III etched on the upper metal plate are all uniform slot arrays, and the three slot arrays have the same period. Moreover, the rectangular slot array I and the rectangular slot array III are symmetrically distributed about the longitudinal direction of the DRPW LWA array, and have the same parameters, including slot length and width, and number of slots.

[0021] Furthermore, the gap size of the rectangular gap array I and the rectangular gap array III is slightly smaller than the gap size of the rectangular gap array II; the number of gaps in the rectangular gap array I and the rectangular gap array III is one less than the number of gaps in the rectangular gap array II; and the distance between two adjacent gaps in the rectangular gap array I, the rectangular gap array III and the rectangular gap array II is half a gap period.

[0022] Furthermore, the dielectric layer consists of three dielectric ridges, forming three energy propagation paths; the three parallel dielectric ridges have the following structural parameters: width... t d and relative permittivity ε r The two media ridges on both sides are completely identical, and their ends are connected to the middle media ridge through a gradually changing media transition section to form a complete media layer; the three sets of rectangular slot arrays are located above the parallel parts of the three media ridges, and the longitudinal central axis of the three sets of slot arrays coincides with the longitudinal central axis of the parallel parts of the three media ridges.

[0023] Furthermore, the upper metal plate and the lower metal plate are made of copper plates with a thickness of 0.5 mm.

[0024] Furthermore, the printed circuit board is used for the design of the dielectric layer, the printed circuit board has a dielectric constant εr = 2.2 and a thickness of 1.575 mm; the three-layer structure is fixed with nylon screws.

[0025] The beneficial effects of this invention are as follows:

[0026] (1) The dielectric ridges of the three waveguide units of the present invention are connected by a gradually changing dielectric transition section to form a complete dielectric layer and are fed by probe. Therefore, the present invention does not require the design of an additional power divider, the feeding is simple and the longitudinal dimension of the array antenna is miniaturized.

[0027] (2) The present invention is a leaky antenna array based on a dielectric ridge parallel plate waveguide design. It utilizes the broadband characteristics of the dielectric ridge parallel plate waveguide and loads a rectangular slot with strong radiation capability to achieve broadband and efficient frequency scanning without the need for additional separate radiation structure design.

[0028] (3) The present invention is a three-element leaky wave antenna array based on a dielectric ridge parallel plate waveguide. Compared with a single leaky wave antenna array element, it can achieve a narrower beam and higher gain, providing better directivity and higher communication quality. Moreover, the three rows of slot arrays of the designed three-element leaky wave antenna array are staggered, which greatly reduces the size of the antenna in the lateral direction, making it easy to integrate with other circuits and realizing the miniaturization of the lateral size of the array antenna. Attached Figure Description

[0029] The present invention includes the following figures:

[0030] Figure 1 A design flowchart of a three-element leaky wave antenna array structure based on a dielectric ridge parallel plate waveguide provided by the present invention;

[0031] Figure 2 This is a schematic diagram of the three-dimensional structure of a dielectric ridge parallel plate waveguide;

[0032] Figure 3 This is a schematic diagram illustrating the principle of the radiation pattern product theorem for a three-element leaky wave antenna array with a dielectric ridge parallel plate waveguide designed in this invention.

[0033] Figure 4 This is a three-dimensional structural schematic diagram of the three-element leaky wave antenna array based on the dielectric ridge parallel plate waveguide of the present invention;

[0034] Figure 5 The S-parameter simulation results of the three-element leaky wave antenna array based on the dielectric ridge parallel plate waveguide of this invention are shown below.

[0035] Figure 6 The above are the simulation results of the overall efficiency of the three-element leaky wave antenna array based on the dielectric ridge parallel plate waveguide of this invention.

[0036] Figure 7 The simulated E-plane radiation patterns of the three-element leaky wave antenna array based on the dielectric ridge parallel plate waveguide of this invention at different frequencies are shown.

[0037] Figure 8 The simulation results of the gain curves of the three-element leaky wave antenna array based on the dielectric ridge parallel plate waveguide of the present invention at different frequencies are shown.

[0038] Figure 9 This is a comparison of the 3D simulated radiation pattern of the three-element leaky wave antenna array based on the dielectric ridge parallel plate waveguide of the present invention at 40 GHz with the 3D simulated radiation pattern of a single dielectric ridge parallel plate waveguide leaky wave antenna element at 40 GHz.

[0039] Among them, 1-upper metal plate, 21-dielectric ridge, 3-lower metal layer; 1-2 rectangular slot array I, 1-3 rectangular slot array II, 1-4 rectangular slot array III, 5-dielectric layer, 6-lower metal plate, 7-probe hole, 8-screw hole. Detailed Implementation

[0040] To make the objectives, advantages, and features of the present invention more apparent, the following description is provided in conjunction with the appendix. Figure 1-9 The present invention will be further described in detail below with reference to specific embodiments.

[0041] like Figure 1 As shown, this invention discloses a three-element leaky wave antenna array structure based on a dielectric ridge parallel plate waveguide, including the following design steps:

[0042] S1. Based on the coupling characteristics of the dielectric ridge parallel plate waveguide, a three-element array structure is designed. The two-port array antenna is fed by probes in parallel.

[0043] S2. Based on the pattern product theorem, the gap design of the three units is determined according to the relationship between gap size and leakage, thereby designing a scanning beam that meets the requirements of narrow lobe and high gain.

[0044] Furthermore, the waveguide array design method in S1 is as follows:

[0045] First, based on the coupling characteristics of the dielectric ridged parallel-plate waveguide (DRPW), a suitable spacing between two adjacent dielectric ridges is selected. p d This allows for the design of a three-element waveguide array with a small lateral dimension while minimizing inter-waveguide coupling effects. In other words, the designed waveguide array exhibits low inter-waveguide coupling while maintaining a compact array structure. The structure of the DRPW is as follows: Figure 2 As shown, it includes an upper metal plate 1, a dielectric ridge 2, and a lower metal layer 3. The coupling effect is determined by the coupling coefficient. C Determining the magnitude of the values, C The propagation constants of the odd and even modes of the DRPW coupled field can be used as a basis. β o and β e Confirmed, the specific formula is as follows:

[0046] ;

[0047] Secondly, the two ends of the dielectric ridges in the three DRPW units of the waveguide array are connected to form a complete dielectric layer. The waveguide array uses a probe parallel feeding method, that is, the probe is placed at the intersection of the three dielectric ridges; and a load is set at the end of the array to absorb the remaining energy transmitted to the end.

[0048] Furthermore, the gap design method in S2 is as follows:

[0049] First, the required radiation intensity difference for the three DRPW arrays is determined according to the pattern product theorem, thereby obtaining a leaky antenna array with a narrower beam compared to a single leaky antenna. Figure 3 This is a schematic diagram of the principle of the pattern product theorem, from... Figure 3 It can be determined that the radiation intensity of the middle leaky antenna element should be greater than that of the two leaky antennas on both sides; and in order to ensure that the radiation pattern is not distorted, the radiation intensity of the leaky antennas on both sides should be consistent.

[0050] Secondly, slot arrays of different sizes are designed on the DRPW array according to the required radiation intensity, that is, slot arrays are etched on the upper metal plate of the three DRPW units. Among them, the radiation capacity of the slot arrays located on both sides should be equal and slightly less than that of the slot array located in the middle.

[0051] Furthermore, such as Figure 4 As shown, the DRPW LWA three-unit array consists of an upper metal plate 1, rectangular slot arrays I1-2, II1-3 and III1-4 engraved on the upper metal plate 1 for energy leakage radiation, a dielectric layer 5, a lower metal plate 6, probe holes 7 for power feeding, screw holes 8 for fixing the overall structure, and some other structures.

[0052] Furthermore, the upper metal plate 1 and the lower metal plate 6 (as a ground plane) form an upper and lower parallel metal plate, and the three units share the upper and lower parallel metal plate. The rectangular slot arrays I1-2, II1-3, and III1-4 etched on the upper metal plate 1 are all uniform slot arrays, and the three sets of slot arrays have the same period; the rectangular slot arrays I1-2 and III1-4 are symmetrically distributed about the longitudinal direction of the DRPW LWA array, and their parameters are exactly the same (including slot length and width, number of slots); the slot size of the rectangular slot arrays I1-2 and III1-4 is slightly smaller than the slot size of the rectangular slot array II1-3; the number of slots in the rectangular slot arrays I1-2 and III1-4 is one less than the number of slots in the rectangular slot array II1-3; the distance between two adjacent slots in the rectangular slot arrays I1-2 (III1-4) and II1-3 is half a slot period.

[0053] Furthermore, dielectric layer 5 consists of three dielectric ridges, forming three energy propagation paths. The structural parameters of the three parallel dielectric ridges (including width) are as follows: t d and relative permittivity ε r The two media ridges on both sides are completely identical, and their ends are connected to the middle media ridge through a gradually changing media transition section to form a complete media layer; the three sets of rectangular slot arrays are located above the parallel parts of the three media ridges, and the longitudinal central axis of the three sets of slot arrays coincides with the longitudinal central axis of the parallel parts of the three media ridges.

[0054] Furthermore, a copper plate is used in the design of the upper metal plate 1 and the lower metal layer 3, with a thickness of 0.5 mm; the Rogers RT5880 printed circuit board is used in the design of the dielectric layer 5, with a dielectric constant of... ε r = 2.2, thickness is 1.575 mm; the three-layer structure is fixed with nylon screws.

[0055] Furthermore, regarding such Figure 4 The working principle of the three-element leaky wave antenna array shown is described in detail below:

[0056] One end of the antenna array is fed by a probe, with energy fed in at the intersection of three dielectric ridges. The input energy is confined within the dielectric region and, after being trisected, is transmitted along the three parallel dielectric ridges, radiating out through three sets of slot arrays. The three sets of slot arrays have the same slot period, therefore the beam pointing angles of the three leaky antenna elements are identical. Because the slot sizes in the two side slot arrays are smaller than those in the middle slot array, and the number of slots on the sides is less than that in the middle, the radiation from the leaky antenna elements on the sides is less than that from the middle. According to the pattern product theorem, this leaky antenna array can achieve a narrower beam. This antenna array is designed to operate in the -1st harmonic range, with a beam angle of... θ This can be described using the following formula:

[0057] ;

[0058] in, β The propagation constant in the DRPW array, k 0 is the propagation constant in a vacuum. λ 0 represents the wavelength in a vacuum. p s This refers to the gap cycle.

[0059] Reference Figure 5 As shown, Figure 5 The proposed three-element leaky antenna array is given.11 |and|S 21 Simulation results show that the proposed antenna array performs well in the range of 24 GHz to 64 GHz. 11 With impedance below -10 dB, it exhibits excellent impedance matching characteristics, enabling the construction of ultra-wideband frequency-sweep leaky antenna designs. Furthermore, within the 24 GHz to 64 GHz range, the antenna array's |S 11 |and|S 21 The values ​​are all below -10 dB, indicating that most of the energy is radiated out through the slot array.

[0060] Reference Figure 6 As shown, Figure 6 Simulation results for the overall efficiency of the proposed three-element leaky wave antenna array are shown. It can be seen that, except for the 51 GHz band, the overall efficiency of the antenna array is above 90%.

[0061] Reference Figure 7 As shown, Figure 7 The E-plane radiation pattern of the proposed antenna array in the range of 30 GHz to 55 GHz is shown. It can be observed that the antenna array can control single-beam frequency scanning from -76° backward to 6° forward in this frequency range. The total scanning range is 82° within the operating bandwidth of 58.8% of the relative bandwidth, which has an extremely wide operating frequency band and strong beam scanning capability.

[0062] Reference Figure 8 As shown, Figure 8 Simulation results of the antenna array gain in the single-beam operating frequency band are shown. It can be observed that the antenna achieves a gain of 10.1 dBi to 18.9 dBi in the 30 GHz to 55 GHz frequency band.

[0063] Reference Figure 9 As shown, Figure 9 A comparison is given between the simulated 3D radiation pattern of the proposed antenna array at 40 GHz and the simulated 3D radiation pattern of a single DRPWLWA at 40 GHz. It can be observed that the antenna array has a significant effect on beam narrowing.

[0064] Specifically, in summary, the proposed three-element leaky wave antenna array based on dielectric ridge parallel plate waveguide achieves narrow beam and high gain beam scanning by utilizing the broadband characteristics of DRPW and array theory. Furthermore, the antenna array has an extremely wide single-beam operating bandwidth and very high antenna efficiency.

[0065] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0066] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A design method for a three-element leaky wave antenna array structure based on a dielectric ridge parallel plate waveguide, characterized in that, The method includes: S1: Design a three-element array structure based on the coupling characteristics of the dielectric ridge parallel plate waveguide. The three-element array structure is a two-port array antenna, which is fed by probes in parallel. S2: Based on the pattern product theorem, the slot design of the three units is determined according to the relationship between the slot size and the leakage amount, so as to design a scanning beam that meets the requirements of narrow lobe and high gain. S1 specifically includes: S11: Select the spacing between two adjacent dielectric ridges based on the coupling characteristics of the dielectric ridge parallel plate waveguide. p d This allows for the design of a three-element waveguide array with a small lateral dimension while ensuring minimal inter-waveguide coupling. In other words, the designed waveguide array exhibits low inter-waveguide coupling while maintaining a compact array structure. The DRPW structure includes an upper metal layer, a dielectric ridge, and a lower metal layer. The coupling effect is determined by the coupling coefficient. C Determining the magnitude of the values, C Based on the propagation constants of odd and even modes of the DRPW coupled field β o and β e Confirmed, the specific formula is as follows: ; S12: Connect the two ends of the dielectric ridges in the three DRPW units of the waveguide array to form a complete dielectric layer; the waveguide array adopts probe parallel feeding, that is, the probe is placed at the intersection of the three dielectric ridges, and a load is set at the end of the array to absorb the remaining energy transmitted to the end.

2. The design method of a three-element leaky wave antenna array structure based on a dielectric ridge parallel plate waveguide as described in claim 1, characterized in that, S2 specifically includes: S21: Determine the required radiation intensity difference for the three DRPW arrays according to the pattern product theorem to obtain a leaky antenna array with a narrower beam compared to a single leaky antenna; the radiation intensity of the leaky antenna element in the middle is greater than that of the two leaky antennas on both sides, and in order to ensure that the pattern is not distorted, the radiation intensity of the leaky antennas on both sides is kept consistent. S22: Design slot arrays of different sizes on the DRPW array according to the required radiation intensity, that is, etch slot arrays on the upper metal plate of the three DRPW units; wherein, the radiation capacity of the slot arrays located on both sides is equal and less than that of the slot array located in the middle.

3. A three-element leaky wave antenna array structure based on a dielectric ridge parallel plate waveguide, characterized in that, The structure includes an upper metal plate (1), on which are engraved an array of rectangular slots I (1-2), II (1-3), and III (1-4) for energy leakage radiation, a dielectric layer (5), a lower metal plate (6), probe holes for power feeding (7), and screw holes for fixing the overall structure (8). The upper metal plate (1) and the lower metal plate (6) form an upper and lower parallel metal plate, and the three units share the upper and lower parallel metal plate. The dielectric layer consists of three dielectric ridges, forming three energy propagation paths. The two ends of the two dielectric ridges on both sides are connected to the middle dielectric ridge through a gradually changing dielectric transition section, forming a complete dielectric layer. Three sets of rectangular slot arrays are located above the parallel parts of the three dielectric ridges, and the longitudinal central axis of the three sets of slot arrays coincides with the longitudinal central axis of the parallel parts of the three dielectric ridges.

4. The three-element leaky wave antenna array structure based on a dielectric ridge parallel plate waveguide as described in claim 3, characterized in that, The rectangular slot arrays I (1-2), II (1-3), and III (1-4) etched on the upper metal plate (1) are all uniform slot arrays, and the three slot arrays have the same period. The rectangular slot arrays I (1-2) and III (1-4) are symmetrically distributed about the longitudinal direction of the DRPW LWA array, and have the same parameters, including slot length and width, and number of slots.

5. The three-element leaky wave antenna array structure based on a dielectric ridge parallel plate waveguide as described in claim 4, characterized in that, The slit size of the rectangular slit array I (1-2) and the rectangular slit array III (1-4) is slightly smaller than the slit size of the rectangular slit array II (1-3); The rectangular slot array I (1-2) and the rectangular slot array III (1-4) have one fewer slot than the rectangular slot array II (1-3); the adjacent slots in the rectangular slot array I (1-2), the rectangular slot array III (1-4) and the rectangular slot array II (1-3) are separated by a distance of half a slot period.

6. The three-element leaky wave antenna array structure based on a dielectric ridge parallel plate waveguide as described in claim 5, characterized in that, The three parallel ridge structures of the dielectric layer, namely the width t d and relative permittivity ε r Exactly the same.

7. The three-element leaky wave antenna array structure based on a dielectric ridge parallel plate waveguide as described in claim 6, characterized in that, The upper metal plate and the lower metal plate are made of copper plates with a thickness of 0.5 mm.

8. The three-element leaky wave antenna array structure based on a dielectric ridge parallel plate waveguide as described in claim 7, characterized in that, The printed circuit board is used for the design of the dielectric layer. The printed circuit board has a dielectric constant εr = 2.2 and a thickness of 1.575mm. The three-layer structure is fixed with nylon screws.

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